EMERGENCY LIGHTING SYSTEM DESIGN CONSIDERATIONS CODES AND STANDARDS

Emergency lighting is required when the normal lighting is extinguished, which can occur for any of three reasons:

1. General power failure
2. Failure of the building’s electrical system
3. Interruption of current flow to a lighting unit, even as a result of inadvertent or accidental operation of a switch or circuit disconnect.

As a result of the third reason, sensors must be installed at the most localized level—that is, at the lighting fixture (voltage sensor) or in the lighted space (photocell sensor).

Codes and Standards
Because emergency lighting is a safety-related item, it is covered by various codes, several of which may
have jurisdiction. In addition, there are widely accepted technical society and industry standards whose recommendations normally exceed the minimal required by codes.

1. Life Safety Code (NFPA 101, 2009). This code defines the locations within specific types of structures requiring emergency lighting and specifies the level and duration of the lighting.

2. National Electrical Code (NFPA 70, 2008). This code deals with system arrangements for emergency light (and power) circuits, including egress and exit lighting. It discusses power sources and system design.

3. Standard for Health Care Facilities (NFPA 99, 2005). This code deals with special emergency light and power arrangements for these facilities.

4. OSHA regulations. These are primarily safety oriented and, in the area of emergency lighting, discuss primarily exit and egress lighting requirements.

5. Industry standards. These include the publications of the IESNA and the IEEE, in particular Recommended Practice for Emergency and Standby Power Systems for Industrial and Commercial Applications (IEEE Standard 446-1995).

Because codes and standards are constantly being revised and updated, the designer for an actual project must determine which codes have jurisdiction, obtain current editions, and design to fulfill their requirements. The following material provides general information and focuses on good practice but is not intended to take the place of applicable construction and safety codes.